Bulk tape erasers for erasing magnetic tape in bulk form, i.e., tape wound up in a reel or on a spool or in a cassette, include an electromagnet which is built up of laminations of silicon-iron in the shape of an "E", the energizing coil being mounted on one outer limb to concentrate the magnetic flux in a narrow but intense strip.
In recent years, various types of magnetic tapes have been developed which require a higher level of magnetic flux to bulk erase than earlier types, and an object of this invention is to provide an electromagnet system having a greater erase flux, capable of erasing such newly developed magnetic tapes without the requirement for a greater input of power to the device and consequently generation of greater heat in the device.